Modern gas turbine engines may offer fuel flexibility in that both natural gas and highly reactive fuels such as syngas and the like may be used. The use of a diverse fuel spectrum provides increased operational flexibility, cost control, plant efficiency, and/or improved emissions characteristics. Such fuel flexibility provides customers with the ability to select a fuel source based upon availability, price, and other variables.
The combustor of the gas turbine engine, however, must be able to accommodate the significant differences between the characteristics of natural gas and syngas such as in Wobbe number and fuel reactivity. For example, the volumetric flow rate for syngas may be more than double the volumetric flow rate for natural gas for the same combustion temperature. As such, the syngas fuel pressure ratios may be extremely high. Moreover, the use of such highly reactive fuels may lead to flame holding and possible nozzle damage.
There is a desire for improved combustor fuel nozzle designs that provide fuel flexibility to accommodate a variety of fuels. The combustor fuel nozzle should be able to accommodate both natural gas and syngas without limiting durability or efficiency. The combustor fuel nozzle preferably provides syngas combustion with comparable performance to natural gas combustion in terms of flow, mixing, dynamics, and emission patterns.